Priming composition



Patented July 26, 1938 UNITED STATES PATENT OFFICE PRIMING COMPOSITIONGeorge C. Hale and William H. Rinkenbach, Dover, N. J.

No Drawing. Original application September '26,

1935, Serial No. 42,284. Divided and this application January 24, 1938,Serial No. 186,708

2 Claims. (CI. 52 1) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) The invention described hereinmay be manutruly homogeneous blend very diificult to obtain. facturedand used by or for the Government for The lack of homogeneity whichoften results in governmental purposes, without the payment to thefiring pin contacting only crystals or par-v us of any royalty thereon.ticles of the nonexplosive constituents of the 5 This invention relatesto priming compositions priming mixture, is one of the main causes of 5for propellent powders and other explosives, and ignition failures orignition delays.

more particularly the use of normal lead dini- It has been consideredthat a marked improvetroresorcinate as the essential constituent of thement in the uniformity of behavior of primer priming compositions.compositions would be obtained if compositions The term primingcomposition commonly recould be formulated so as to contain only explo-10 fers and refers herein to an explosive composisive constituents. Itwas believed that if all nonti-on used to effect ignition of apropellent powder explosive oxidizing agents, fuels, and abrasives orother explosive. It is the function of a primor sensitizers could beeliminated and only sensiing composition to deliver intensely hot,flaming tive explosives used, the difficulty of attaining gases whencombustion of the composition is inithe highest degree of homogeneitywould be elimlo tiated by the impact or stab of a firing pin or inated;if all particles of the composition were other firing device. It is notrequired that the sensitive explosives any particle struck by thecomposition detonate or produce highly brisant firing pin would readilyignite. An extension 2 effects; in fact such effects are definitelyavoided of this idea led to the belief that the ideal wouldcompositions. Thus the sensitive, highly brisant alone, would provideall the characteristics reexplosives such as mercury fulrninate, leadazide, quired of a primer composition, i. e. the high delead styphnate,and hexanitromannite have never gree 0f s ty to impact, the pid rate ofbeen used alone as priming compositions but it burning. the inability todetonate under the Conhas been general practice to employ such so calledditions of use, etc. We have discovered that 25 detonating agents inadmixture with other manormal lead dinitroresorcinate has combined interials which will reduce the brisant effect of the se f a t propertiesqu d for certain uses detonating agent and provide a sensitive primingof a pr Composition Which ust function mixture which will burn ratherthan detonate un er a s a or flame a It is i n y under the conditions ofuse. Apparently only sensitive to impact or flame that it ignites underone other type of priming composition has been the conditions availablein ammunition, it burns used viz., a mixture of oxidizing agents, fuelsp y W t out p ducing objeotional brisant or and sensitizing agents noneof which alone are blast e ts Comparing s y Wit Standard milexplosive,or at least capable of detonating, but i ry pri r compositions n this pt. It is whi h h mixed become sensitive to ignition insoluble in water,does not absorb moisture from 35 and burn rapidly with intense heateffects. the air, and leaves no objectionable residue in the There is afundamental objection to the two bore of the guns. Since it aloneprovides these types of priming mixtures referred to which havecharacteristics its use eliminates the hazard of been used up to thepresent time in that it is mixing, always present in the manufacture ofextremely difiicult to provide the intimate mixing previous types ofprimer compositions. The

f ingredients necessary to Obtain the degree of chemical formula fornormal lead dinitroresoruniformity desired. When it is considered thatcinate is as follows; many primers are expected to fire from the stab ofa sharp pointed firing pin which contacts only a very small part of theprimer charge, which is present itself in only minute amount it isapparent that the maximum uniformity in composition is required if theprimers are to function uni- Non formly. Yet as mentioned above thecompositions in general use at present almost invariably It may beprepared by f of a lead Salt 50 contain three or four nonexpmsiveconstituents such as lead nitrate on sodium dlmtroresorcinate. such asground glass, antimony sulphide, calce primers are used in y difierenttypes cium silicide, barium nitrate, etc., having widely of ammunitioncomponents such as military fuzes, different specific gravity, hardness,crystal form small arms cartridges, etc., it was recognized that andother physical characteristics which make a the lead dinitroresorcinatemight not serve all of 55 by the common methods of formulating primingbe attained if an explosive could be found which, 29'

these difierent purposes with the same degree of efficiency and aneffort was made to modify its speed of action and sensitivity byemploying it in mixture with other materials. It was found that suchmixtures can be prepared which vary markedly in brisant efiects withoutlosing the degree of sensitivity required for consistent functioning.Compositions comprising the lead dinitroresorcinate in admixture withfinely divided black powder, in admixture with tetracene-and inadmixture with nitrocellulose have been found to function efiicientlyand with various speeds of action and with the production of anincreased volume of gaseous products. A comparison of the behavior ofthe new compositionscontaining lead dinitroresorcinate, with acomposition of the type in general use at present is shown in thefollowing table:

Composition Egg $522 Impulse Gas volume Co. 1 Lead dmitroresorcinata.100 2. 1.9 4. 4

2 Lead dinitroresorcinate 75 3. 5" 3. 3 6. 4

Black powder 25 3 Lead dinitroresorcinate. 75 3. 0" 2. 12" 4. 50

Tetracene 25 4 llxlezrcury fulgllinafie o assium c are e Antimonysu1phide 21 0 8" 25 Ground glass 31 To facilitate loading, 2% of shellacin alcohol solution was added to moisten and bind the compositions.

Composition No. 4 is listed above as representative of the type in useat present and for comparison with the new compositions developed. It isnoted that composition No. 1 comprising lead disitroresorcinate alonehas even a higher degree of sensitivity than composition No. 4,substantially the same impulse value or brisant effect and a higher gasvolume, while compositions 2 and 3 are intermediate in sensitivitybetween compositions 1 and 4 and have appreciably higher impulse and gasvolume values than composition No. 4. It is thus indicated that the newcompositions cited do not merely duplicate but are superior to thepresent type of composition No. 4 in both sensitivity and gas volume. Inaddition these new compositions are entirely free of ground glass,antimony sulphide or any other non-explosive material a particle ofwhich may be contacted directly by a firing pin and thus lead to failureof the primer to ignite. An additional outstanding advantage of thesecompositions results from the resistance of lead dinitroresorcinate todecomposition. It has been found to have stability far superior tomercury fulminate and other sensitive explosives commonly used in primercompositions.

In general, any dinitro compound is much less sensitive than a trinitrocompound and for this reason the latter type of compound is usuallyfound in primer compositions. However, we discovered that leaddinitroresorcinate is even more sensitive than the trinitroresorcinol orthe lead salt of trinitroresorcinol While having only approximatelyone-sixth the brisance. Accordingly it is more suitable in use forpriming compositions where initiation is effected by the stab of afiring This application is a division of our co-pending applicationSerial Number 42,284, filed September 26, 1935, and now issued as PatentNumber 2,116,514 dated May 10, 1938.

We claim:

1. A priming composition consisting of normal lead dinitroresorcinate75% and tetracene 25%.

2. A priming composition consisting of normal lead dinitroresorcinateand tetracene.

GEORGE C. HALE. WILLIAM H. RINKENBACH.

